package com.lxk.concurrency.example.lock;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import com.lxk.concurrency.annoations.ThreadSafe;

/**
 * @Description 并发量少，使用 synchronized；并发量不大，但是趋势可以预估，使用 ReentrantLock 
 *
 * @author 堆堆堆
 * @date 2018年5月25日 上午11:32:28
 */
@ThreadSafe
public class LockExample2 {

	// 请求总数
	public static int clientTotal = 5000;

	// 同时并发执行的线程数
	public static int threadTotal = 200;

	public static int count = 0;

	private final static Lock lock = new ReentrantLock();

	public static void main(String[] args) throws Exception {
		ExecutorService executorService = Executors.newCachedThreadPool();
		final Semaphore semaphore = new Semaphore(threadTotal);

		final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);

		for (int i = 0; i < clientTotal; i++) {

			executorService.execute(() -> {
				try {

					semaphore.acquire();
					add();
					semaphore.release();

				} catch (Exception e) {
					System.out.println(e);
				}
				countDownLatch.countDown();
			});
		}
		countDownLatch.await();
		executorService.shutdown();

		System.out.println("count:" + count);
	}

	private static void add() {

		lock.lock();

		try {
			count++;
		} finally {
			lock.unlock();
		}

	}
}
